Die for forging



UNITED STATES PATENT OFFICE,

HENRY H. FORSYTH, OF` PITTSBURG, PENNSYLVANIA.

`DIE FOR FORGING.

SPECIFICATION forming part of Letters Patent No. 384,751, dated J une 19, 1888.

Application tiled March 1, 188B. Serial No. 265,819.

To @ZZ whoml it may concern,.-

Beit known that I, HENRY H. FoRsYTH, of the city of Pittsburg, in the county of Allegheny and Stateoi'Pennsylvania,haveinvented a new anduseful Improvement in Dies; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to an improvement in dies for forging or swaging pieces of'iron or steel which are of circular cross-section and either of cylindrical, conical, or irregular longitudinal section. Heretofore it has been the practice in forming such articles to use two dies of similar contour, the edges of the working-cavities of which come into contact in the operation of the dies. The article to be forged-.- for example, a piston-rod, an axle, or the likeis placed on the lower die, and the upper die or hammer is caused. to beat upon it, the iron meanwhile being turned on the bed-die. The difficulty in the use of these dies is thatwhen the conjoined cavities are circular in crosssection they are apt to form [ins on the surface of the article. This has caused manufacturers generally to employ dies with elliptical working-cavities, so made in order to avoid the for mation of fins; but the use of the elliptical dies 'is disadvantageous in that it is hard to produce by them articles of uniform circular crosssection, and in any case the contact of the dies batters the -edges of the cavities and soon impairs their eficiency Where great accuracy of outline and smooth ness of surface are required.

The object of my invention is to cure this defect and to provide dies by whose use`a perfectly round and uniform article can be produced.

In the accompanying drawings, Figure 1 is a vertical cross-section of my improved dies shown in conjunction.` Fig. 2 is a plan view of the lower die. Fig. 3 is a plan view of the lower die modied in order to adapt it to the manufacture of tapered articles. Fig. 4 is a vertical sectional view similar to Fig. l, illustrating a modified form of the dies.

Like symbols of reference indicate like parts in each.

Referringmow, to the drawings, 2 represents the upper die,and 3 the lower die. The Work ing-face 4 of the lower die is made with a curved contour on the are of acircle, the curve being (No model.)

tion, and from the top of the semicircle the bottom die extends upwardly and outwardly in iaring lines 5. The working-face of the upper die, 2, is also made with a curved contour whose cross section is that of the arc of a circle somewhat less than a semicircle. The edges of the cavities of the dies are separated by recesses 11, which communicate with the cavities, and while not substantially impairing the general circular shape in crosssection of the conjoined cavities, yet part the edges and prevent the formation of fins on the article. From the extremities of the cavity 6 of wardly and outwardly on diverging lines 7. These cavities need not be contiuuouslyarcs of a circle, for they may be made ridged or polygonal, but it will be vfound that the nearer preferably .nearly semicircular in cross-sec lthe lower die the body ofthe die extends upthe approximation to the circle the better will p be their operation.

In order that the faces of the dies shall not meet in their work of hammering, I provide them with shoulders 8 9 at their outer sides, which shoulders meet when the moving die is in action, and by receiving the impact of the blows prevent the working-faces of the dies from coming into contactand from being injured. In order to save these shoulders from injury as much as possible, I prefer to face the shoulders 9 with plates 10 of copper, or some other soft metal, which are set in recesses on top of the shoulders, and by opposing a soft body to the action of the moving upper die serve as buffers. Instead of having these shoulders S and 9 in connection with the bodies of the dies, I may substitute therefor suitabley stops on the plunger or on the slide or pistonrod, which will act in substantially the same way to produce the same result.

The operation of the dies is as follows: In order to forge a bar of iron into the proper cylindrical shape, supposing the diecavities to be constant in cross-section, the bar is laid on the inclined faces 5 of the lower die, 3, and

the upper die, being actuated by a suitable Workman or by suitable machinery continually during this operation, and the eiect of IOO the upper die, acting in conjunction with the inclined faces 5, is gradually to diminish the diameter of the bar'and to bring it more nearly to a circular form, and finally to force it into the cavity of the lower die,which, in conjunction with the correspondingly-curved cavity of the upper die, gives the barits finished cir cular form. I am enabled thus to successfully employ dies the general contour of the crossseetion of whose conjoined Working-cavities when the dies are most nearly in contact is substantially circular, to conform to the section of the finished article, the conjoined cavities having parted or recessed sides, and thus I get all the advantages of the circular dies without the disadvantages which have heretofore attended their use. This I am enabled to do by reason of the use of the inclined side faces, 5, and by reason of the fact that the working-faces of the dies do not come in contact at the edges. If they should comein contact the effect would be to flatten out the metal bar, to produce fins on it, and to spoil the dies without attaining the desired result. I believe that I am the iirst to dissociate the edges ofthe operative faces of the dies from the stop which limits their approach. This is a very important feature of my invention, since it enables me to make the articles of true circular form in cross-section, and also to prevent the dies from becoming battered or misshapen. In case the article to be produced is not of cylindrical but is of tapering` form-such as a wagonaxlee-the operationis the same, except that the dies, instead of having working-faces with cavities of constant width, have cavities conforming to the shape of the article, as shown in Fig. 3. For producing` articles of other forms in longitudinal section the dies are correspondingly modified, as will be readily understood.

My invention is susceptible of many modications,not only in change of shape ofthe dies to correspond to the change in shape ofthe article produced, but also in other changes of form of the parts. For instance, the recesses 11 at the sides of the workingcavities of the dies are solely for the purpose of preventing contact of the working faces and may be greatly modified in form, and instead of hav ing the dies arranged as shown in the drawings they may be reversed, the presentlower die being used as the upper die, and vice versa.

I illustrate a modification in form ofthe recesses in Fig. 4, in which the inclined faces 5 and 7 of the dies are not used`and the recesses ll are enlarged. Other modifications will suggest themselves to those skilled in the art.

My invention is of great practical utility and will be appreciated by those skilled in the art. It may be used not only for the purpose of forging hot met-als into the proper shapes, but for finishing articles by cold-hammering. This last named feature makes it especially desirablein the manufacture oftapered iron axles and other articles of irregular longitudinal section. Hammering by means of these dies preserves the desirable hardness of the article.

I do not claim herein, broadly, dies having their working-faces provided with semicircular cavities, nor do I limit the scope of my claims to dies having working-cavities made on the arcs of a circle, unless expressly so stated therein, since, if the stops be used,the working-cavities of the dies may be otherwise shaped, my invention in this regard relating to the construction of the dies by which the edges of the cavities are prevented from coming into contact, and by which I am enabled, if desired, to use Adies the general contour of whose conjoined working-cavities is substantially ci rcular in cross-section.

I claim-- 1. An improvement in dies for forging or swaging, which consists in the combination of dies whose opposing faces are provided with suitable working-cavities made substantially in arcs of a circle, the general contour of the conjoined die-cavities when the dies are most nearly together being substantially circular, the edges of the cavities of the dies being separated by lateral recesses, substantially as and for the purposes described.

2. An improvement in dies for forging or i swaging straight metal articles, which consists in the combination Vof dies whose opposing faces are suitably formed and stops whereby the motion of the movable die is limited and the edges of the working-faces are prevented from coming into contact, substantially as and for the-purposes described.

'3. An improvement in dies for forging or swaging straight metal articles circular in cross-section and either of const-ant or varying longitudinal section, which consists in the combination of dies whose opposing faces are provided with cavities, the cavity of one of the dies having flaring extensions, substantially as and for the purposes described.

In testimony whereof I have hereunto set my hand this 25th day of February, A. D. 1888.

HENRY H. FORSYTH.

Witnesses:

THoMAs W. BAKEWELL, J. K. SMrrH.

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